Record daily rainfall in 100 years - Berkshire, 18 August 2011
 

My checkgauge total 0900-1800z today was 66.2 mm.

(Standard and well-exposed climatological station site - MetO and EA
rainfall site 270162, last inspected in 2010.)

Total from my two TBRs 66.0 mm and 60.2 mm. My Davis VP2 AWS TBR
managed only 38.2 mm: not sure why the big difference, but it
certainly shows the necessity for a deep-funnel checkgauge to get an
accurate standard reading in torrential rainfall.

This is not only my ‘personal’ highest 09-09 fall in 40 years
observations, but the highest 09-09 fall on my local unbroken daily
records back to 1910; the previous highest was 58.4 mm in a
thunderstorm on 6 August 1982.

There have been higher falls split across 09-09 periods, most recently
20 July 2007 of course, with 81.1 mm in just under 15 hours.

Peak intensity 80 mm/h at 1214z; but 60 mm/h was attained for only 49
sec in all. Highest hourly fall 30.4 mm (60 min from 1157z), just
exceeding the previous record (at this site since 1987) of 30.2 mm on
20 July 2007. Highest clock-hour fall 29.6 mm commencing 1200z.

The day max 09-18h of 13.4 °C also equalled the August 09-09h record,
set on 3 August 1986, although it seems likely to be exceeded by 0900
tomorrow morning.

Regards
Stephen

Record daily rainfall in 100 years - Berkshire, 18 August 2011
 

Thanks Stephen, that is really most interesting. Yet another example of
extreme rainfall occuring on N or NW flank of a slow moving low in summer
with a warm front or warm occlusion draped around it.
Of course the low temperatures and rain went together after a chilly night
and a cloudy start.

Will
--

Record daily rainfall in 100 years - Berkshire, 18 August 2011
 

On Aug 18, 8:18*pm, Stephen Burt wrote:
My checkgauge total 0900-1800z today was 66.2 mm.

(Standard and well-exposed climatological station site - MetO and EA
rainfall site 270162, last inspected in 2010.)

Total from my two TBRs 66.0 mm and 60.2 mm. My Davis VP2 AWS TBR
managed only 38.2 mm: not sure why the big difference, but it
certainly shows the necessity for a deep-funnel checkgauge to get an
accurate standard reading in torrential rainfall.

This is not only my ‘personal’ highest 09-09 fall in 40 years
observations, but the highest 09-09 fall on my local unbroken daily
records back to 1910; the previous highest was 58.4 mm in a
thunderstorm on 6 August 1982.

There have been higher falls split across 09-09 periods, most recently
20 July 2007 of course, with 81.1 mm in just under 15 hours.

Peak intensity 80 mm/h at 1214z; but 60 mm/h was attained for only 49
sec in all. Highest hourly fall 30.4 mm (60 min from 1157z), just
exceeding the previous record (at this site since 1987) of 30.2 mm on
20 July 2007. Highest clock-hour fall 29.6 mm commencing 1200z.

The day max 09-18h of 13.4 °C also equalled the August 09-09h record,
set on 3 August 1986, although it seems likely to be exceeded by 0900
tomorrow morning.

Regards
Stephen

-----------------------------------------------------------------------------------------------------------------
Seems a curiously large total Stephen. Were there any other stations
in Berkshire that measured so much?
It seems to rate with the well publicised flash flood rainfall of 60
mm at Portland, quite a distance from you?

It must have been very localised and embedded on a small scale.
Possibly less than 10 km.

Models did not predict such large totals. More's the pity.

Len Wood
Wembury, SW Devon

-----------------------------------------------------------------------------------------------------------------

Record daily rainfall in 100 years - Berkshire, 18 August 2011
 

On Aug 18, 8:18*pm, Stephen Burt wrote:
My checkgauge total 0900-1800z today was 66.2 mm.

(Standard and well-exposed climatological station site - MetO and EA
rainfall site 270162, last inspected in 2010.)

Total from my two TBRs 66.0 mm and 60.2 mm. My Davis VP2 AWS TBR
managed only 38.2 mm: not sure why the big difference, but it
certainly shows the necessity for a deep-funnel checkgauge to get an
accurate standard reading in torrential rainfall.

This is not only my ‘personal’ highest 09-09 fall in 40 years
observations, but the highest 09-09 fall on my local unbroken daily
records back to 1910; the previous highest was 58.4 mm in a
thunderstorm on 6 August 1982.

There have been higher falls split across 09-09 periods, most recently
20 July 2007 of course, with 81.1 mm in just under 15 hours.

Peak intensity 80 mm/h at 1214z; but 60 mm/h was attained for only 49
sec in all. Highest hourly fall 30.4 mm (60 min from 1157z), just
exceeding the previous record (at this site since 1987) of 30.2 mm on
20 July 2007. Highest clock-hour fall 29.6 mm commencing 1200z.

The day max 09-18h of 13.4 °C also equalled the August 09-09h record,
set on 3 August 1986, although it seems likely to be exceeded by 0900
tomorrow morning.

Regards
Stephen

Rainfall here (NE Surrey/Gt London border) was at a guess
less than 0.5 mm (no automatic instruments). However, the afternoon
was extremely gloomy, almost needing the light on at 4 pm. Very
ominous but it came to nothing. A very cool afternoon "spoilt" by a
max of 17.5°C at 1100Z, otherwise 13-14.
I remember 3 Aug 86; heavy thunderstorm, max 14, moderate
NE'ly and almost daytime darkness for a spell while Amsterdam,
according to VOLMET, had a temperature of 34°C with Brussels and Paris
not far behind.

Tudor Hughes, Warlingham, Surrey.

Record daily rainfall in 100 years - Berkshire, 18 August 2011
 

In relation to your Davis VP2

Just wondered if its a wireless setup the signal may have been lost
during peak rainfall. Mine certainly did until I added a repeater
station.

Just a thought ?

P.S I had 0.1mm yesterday !

Paul C
Brampton, Cumbria
www.bramptonweather.co.uk